test-drb May 2008

test-drb@ccmp.vtda.org

199 participants
350 discussions

Hosting data book scans (was Re: DEC8235 and MM57109N ICs)

by aek＠bitsavers.org

> My preference for distributing large trees of files is > rsync, since it's designed for that, and it lets you efficiently > update an existing local copy with as little data transferred as > possible -- which is great for things like Bitsavers that are > constantly being added to. Which is working quite well.. > so it certainly sounds like a worthwhile project to me. "Voltsavers" The issue isn't who hosts it, but the bandwidth issues. There are hundreds of data books, and they are running about 100mb each when scanned. It is impractical for me to burst them into smaller chunks due to the time it would take to do it. I've had little luck getting people to work on postprocessing the scans in the past. Currently, about 1/3 of everything I have scanned is on bitsavers. It takes about a week to process what I can scan in a day. On an average scanning day I can scan 5-10 thousand pages. I've been scanning now for over 9 years (obviously, not every day).. Because of the thinness of the paper used, a box of data books is over 10k pages. This should give you an idea of the magnitude of work involved in scanning a large databook collection..

16 years, 2 months

DEC8235 and MM57109N -- warning

by tiggerlasv＠aim.com

Be careful when using broker websites for semiconductors. In my search for some SMC UARTS, I've come across some sites that appear to have "open registration" for posting inventories. (i.e., anyone can supply an inventory list, and an e-mail address, and they'll show up on the vendor search.) (Recently digchip dot com ) After submitting a few RFQ's, I received replies from a number of different "companies" (read: individuals) that were highly suspect. For example: Generic e-mail addresses. References to what are supposed to be their "corporate" website, but are in fact unrelated. Payment terms "T/T" (wire transfer) or Western Union. I also received nearly identical quotes, from two presumeably different companies. While this is certainly possible, the verbage used was almost exact. As with any other transaction. . . . "buyer beware". As info. . . . T

16 years, 2 months

DEC8235 and MM57109N ICs

by cclist＠sydex.com

> Date: Thu, 15 May 2008 12:54:34 -0700 (PDT) > From: "Eric Smith" > Bittorrent doesn't help at all for things that only a few (less than > about five) people are trying to download at the same time. FTP is > generally *more* efficient than bittorrent for that. Agreed. When you have a small community who have interest in a BT file and most of the interested people have picked it up already, you can grow whiskers waiting for a seed to emerge. I've seen some rather pitiful begging on the 'net for a seed for such-and-such a file. Sometimes you do find a seed, but he's got his upload throttled down to something like 3Kb/second. It'd be faster to get the file via Aldis lamp. The idea behind BT is utilizing the power of a mob, er "swarm". Three isn't a swarm. Cheers, Chuck

16 years, 2 months

Leakproof cells, was: Osborne OCC1 problem

by cclist＠sydex.com

> Date: Thu, 15 May 2008 17:40:28 +0100 > From: "Ade Vickers" > Or, of course, I could bodge my universal power supply into powering the > multimeter...... (don't dare suggest buying a battery! ;)) This reminds me of a question I've been meaning to ask the list. I've got some old gear that take single D- or C-sized carbon-zinc cells, usually as some sort of minimal-current supply. For example, my VTVM uses one for its resistance function. (Sometimes a high- impedance meter with a real needle is hard to beat). I don't keep cells in this old stuff because I use it only occasionally. Is there such a thing as a long-life leakproof battery that I can use? Silver-zinc perhaps? Thanks, Chuck

16 years, 2 months

Dayton Hamvention

by marvin＠west.net

I finally got my selling spot this afternoon after about a 2 hour wait in line (3303.) I must have missed any other selling spots except for Patricks, but I'll check and drop by :). I have nothing classic computer related this year, but I also should get a chance to look around!!!

16 years, 2 months

Funny Tek 2445 scope problem

by mcguire＠neurotica.com

On Thu, May 15, 2008 2:07 pm, Roy J. Tellason wrote: >> > Case solved (I think). It seems to matter where I ground the >> > probe. I >> > pulled all of the boards out of the system, no change. I then >> > grounded the >> > probe to the middle finger of the voltage regulator on the board >> > and the >> > sine wave went away. >> >> The chassis may not be at digital ground. >> >> Also watch out for the middle lead of three-terminal (78xx/79xx) >> voltage regulators...it's not unheard of to bring them up above >> ground a bit with a voltage divider to make them operate at different >> voltages. > > The _middle_ lead is not ground on the 79xx parts! You're correct of course; I should've said "ground" lead. -Dave -- Dave McGuire Port Charlotte, FL

16 years, 2 months

DEC8235 and MM57109N ICs

by djg＠pdp8.net

>Does anybody know if the DEC8235 is the same as the National DM8235? > Doesn't look likely. The DM8230 isn't the same as the Signetics 8230. The DEC82xx parts seem to be the Signetics 82xx parts. >Mouser claims to be able to order NTE8235, but there's no order pending or >delivery date. ($9.09 each.) > http://www.rselectronics.com/ seems to claim stock. This company search says they have non NTE parts. I used them in 1999 to get a part and the minimum order then was $50. http://www.hrent.com/inv.htm Who knows what has changed since then, the search is using an outside site. They also list the MM57109N from another message. Post back if you do use them.

16 years, 2 months

DEC8235 and MM57109N ICs

by dm561＠torfree.net

---------Original Message: From: Dan Roganti <ragooman at comcast.net> Subject: Re: DEC8235 and MM57109N ICs Gordon JC Pearce wrote: > Does anyone have the datasheet for an MM57109? How hard would it be to > make a replacement, either with an FPGA or a microcontroller or > something? > I've had no luck whatsoever in finding a datasheet for this part. I've been searching online for a long time too. I only have the programming info from old projects. But I too like to get the complete datasheet to check everything. I'm hoping the folks at Area51esg would have a lead on this. =Dan ---------Reply: Well, considering the MM57109 is a microprocessor, it's a little more than just a data_sheet_ unless you only want the pinout & logic diagram. It's one of the COPS family and should be in any NSC MOS databook of the time; if you can't find it and Area51esg can't supply it, contact me off-list and I'll try to find time to scan it, abt. 24 pages. mike

16 years, 2 months

Dayton Hamfest

by pat＠computer-refuge.org

... is tomorrow! Is anyone planning on going this year? I'll be there again, in spaces 3435/3436, and have a bunch of fun old electronic and computer crap (including a few nice, fun, big UNIX boxes). Pat -- Purdue University Research Computing --- http://www.rcac.purdue.edu/ The Computer Refuge --- http://computer-refuge.org

16 years, 2 months

Funny Tek 2445 scope problem

by cclist＠sydex.com

On 15 May 2008 at 12:00, cctalk-request at classiccmp.org wrote: > Date: Thu, 15 May 2008 11:48:42 -0400 > From: Allison > case ground may not be circuit ground... make sure the the probe ground > is actually circuit ground. > > Many machines made the case RF ground and seperate from teh DC ground > using capactiors (true for altair, NS* horizon, CCS, Compupro that I > have). That's my guess also. That 70v 60Hz signal probably doesn't represent anything more than stray AC pickup by the case. Find the real signal ground. A couple of weeks ago, I was working on a friend's old Roland analog synthesizer and discovered that there were *two* grounds on the thing- -digital and analog. And they weren't the same. Neither one corresponded to case ground or even the sleeve on the audio output jacks. Fortunately, both grounds had labeled TPs on the PCBs. Cheers, Chuck

16 years, 2 months

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test-drb May 2008